Plate-type heat exchangers for cooling an oil with a heat exchange fluid are well known. In vehicular applications, such heat exchangers are often mounted on a planar, stamped metal base plate, for example by brazing, to form a heat exchanger module. The heat exchanger module may then be mechanically mounted to a transmission or engine housing, with the base plate providing the module with structural rigidity.
The base plate may include one or more fluid openings providing direct flow communication between one or more fluid manifolds of the heat exchanger and one or more fluid ports of the transmission or engine housing, thereby at least partially eliminating the need for fluid lines and fittings. In a typical structure, the oil outlet port of the transmission or engine housing is in flow communication with the oil inlet manifold of the heat exchanger through an oil inlet opening of the base plate.
A one-way pressure actuated valve may be mounted between the oil outlet port of the transmission or engine housing and the oil inlet manifold of the heat exchanger in order to permit pressurized oil to flow from the engine into the heat exchanger, and to prevent backflow from the oil inlet manifold to the outlet port of the transmission or engine housing. Such anti-drain valves typically have a cylindrical valve housing which is connected directly to the metal base plate of the heat exchanger and project from the bottom surface of the base plate into the oil outlet port of the transmission or engine housing.
Anti-drain valves are required to form a fluid-tight sealed connection with the base plate. In order to achieve a fluid-tight connection with the base plate, it is believed necessary to form the valve housing from a metal which can be sealingly joined to the base plate, for example by brazing or swaging, or by integral formation of the housing and the base plate. Therefore, conventional anti-drain valves typically comprise a housing in the form of a cylindrical aluminum sleeve which is integrally formed with an aluminum base plate or which is brazed or swaged thereto. The internal components of the valve may be supplied as an integral assembly which is then inserted into the housing, for example by press-fitting. Examples of such valves are disclosed in commonly assigned US Publication No. US 2015/0129164 A1 (Ollier), published on May 14, 2015.
While some of the internal components of the valve may be formed from relatively inexpensive materials such as plastics, the need to form the valve housing from metal and to join it to the base plate by brazing, swaging or integral construction are serious limitations which result in higher material costs and additional manufacturing steps, thereby increasing the cost of the heat exchanger module. In addition, the need for a cylindrical metal housing limits opportunities to achieve improvements in construction of the valve, such as the integration of the housing with other valve components, and therefore limits opportunities to achieve cost reductions in the construction of the valve.
Therefore there is a need for an improved construction of heat exchanger modules, and a particular need for anti-drain valves which have a simplified construction and avoid costly manufacturing steps, while providing a fluid-tight sealed connection with the base plate.